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Soften that Foster Horn in an Avatar cab

Discussion in 'Amps and Cabs [BG]' started by LoveThatBass, Dec 18, 2004.


  1. I spent $19.95 plus S/H for a crossover network. I now have a smoother sound from the Foster Horn Tweeter. It blends the speaker and horn nicely. The Crossover will switch between 4 and 8 ohm for the Speaker and works with an 8 ohm horn tweeter. It is two way. I personally used both sections but you can just hook the horn tweeter to the board for a high pass. Note: this replaces the single cap. It will need to be removed. The board has a +/- input, speaker +/- out, and tweeter +/- out. I connected the tweeter output to the pot then from the pot to the Horn Tweeter. I did notice it is so smooth and even sounding that I just turned the pot to max. The buzzing has all but dissappeared, harshness gone, distortion gone now. The pot could really be replaced with a switch to cut the horn in and out for preference. I added a fuse holder with a 4 amp slow blow fuse to the horn circuit for protection.

    http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-146
     
  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Thanks for the tip! I too noticed a happier Foster horn when I built a 2x10 using an SWR crossover (18 dB/octave) instead of the single cap 6 dB/octave crossover that Avatar uses. I bought the horn from Dave so it is identical to the one that he uses in his cabinets.

    I was about to replace the Fosters in my two Avatar 2x10s, perhaps I'll just swap out the crossovers instead...
     
  3. My next step was to ditch the Foster if this did not work...no need for that now...they are doing a fine job now.
     
  4. I recently bought a Neo 2x10, and I'm quite intrigued by this. At $20, even though the horn insn't a big issue for me, I wouldn't mind this small investment.

    How hard was it to install? Do you think someone with no real electronic knowledge could, though is ever slightly experienced with a soldering iron, could accomplish this new crossover deal?

    Thanks.
     
  5. Yes, if you can solder you can do it. I could draw you a diagram when I get back to work and send it to you in Microsoft Word format. To connect to the board you can solder or use push-on lugs that crimp to the wire (available at autozone, Lowe's, Home Depot or Ace Hardware). You will have to remove a speaker to gain access to the inside for mounting (4 wood screws mount board to back of inside of cab). It is fairly simple.
     
  6. Hey, don't bother yourself to do that. I'm definitely thinking about it. I'll email or pm you if I decide to follow through with it, if that's alright.

    Thanks.
     
  7. NJL

    NJL

    Apr 12, 2002
    San Antonio
    nice thread!

    :)
     
  8. Ladynred,
    I do not mind. I can even post it where you just click on the link if that helps you any.
    I enjoy just helping others.
     
  9. This goes for anyone who needs help with this mod.
    My email is open
    gary-ats@sbcglobal.net

    Gary
    Avrett Technical Specialties
     
  10. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Did you try running the woofers full range (the way that most bass cabinets operate) or did you just connect the crossover as it was intended to be used?

    Did you connect your tweeter in phase? In some PMs that I'd exchanged with Bruce Wane on this subject, he suggested connecting the tweeter out of phase since a 12 dB/octave crossover creates a 180 ° phase shift for the high pass section. I believe that Eden connects their tweeters out of phase.
     
  11. I tried it both ways, woofer direct and from output of crossover. Little difference, in fact no noticeable difference Since the speaker tops out at 3500 anyway.
    Yes, I tried it out of phase and in phase. Direct from the board it is connected as manufacturer intended (in phase). With an extra cap in series with the output it had to be connected out of phase for best sound. I removed that original cap that Avatar put on and connected it in phase. It sounds very good.
     
  12. dcr

    dcr Supporting Member

    If the speaker tops out at 3.5 kHz, and the XOVR bottoms out at 3.5 kHz, doesn't that almost leave a "hole" or "scoop" around 3.5kHz?

    Or is there enough overlap due to slope of freq. response curve to not be too noticeable?

    dcr
     
  13. How do you scoop when the horn comes in a 3500 hz? Without the horn..you have just low end tonal characteristics. The crossover doesn't just shut off dramatically or turn on dramatically. Prior to puttting this on I noticed a definate harshness where the horn was trying to produce lower notes. With this crossover...the sound is smoothly blended. No noticeable scoops or assentuations as before.
    This crossover is more suffisticated than the simple capacitor that passed Higher frequencies to the horn...it uses the cap in series with the horn and a coil (to trap the lows) in parallel with the horn..likewise on the speaker portion it uses a coil to pass low frequencies in series with the speaker and a cap in parallel to trap or shunt higher frequencies. The result is a smoother working speaker and horn as they are not striving to produce things they were not designed for. As you near 3.5K the speaker "Starts" to shut down while the horn "Starts" to turn on. As you pass 3.5K the speaker is shutting down while the horn is turning on..sort of like Passing the ball to another player who can produce results better in that area.
    Hey, not trying to sell this to anyone. I am now very happy with the sound. If you are happy with it as it comes stock..great! I was not. The horn was "Buzzy", distorted if you turned the bass controls up and hit certain notes, and was harsh sounding to my ears (I believe because it was forced to produce what it was not made for). I tried the 3K version first.. While better, the horn still distorted with low notes. I put the original cap in series which helped but did not quite eliminate this. The 3.5K version of this crossover works perfectly without the aid of the stock cap in series.
     
  14. dcr

    dcr Supporting Member

    Oh no, please don't misunderstand! I was just curious about the crossover points. In fact, I went back and re-read and saw your original post where you discussed your trials with the 3 kHz version. I find the idea intriguing, and certainly plan on trying it myself.

    I've been following 2-3 of these threads on Avatar tweet mods, as I have two of the Avatar cabs myself. To me, they're okay stock, but just okay. Like a lot of guys, I'm in a constant search for the perfect sound. I've started collecting parts to start some mods AAMOF. I'm wanting to try the Peerless tweeter replacement trick, but don't want (read too lazy) to cut out a backing plate to mount the smaller Peerless tweeter in.

    It appears that this mod will accomplish a lot of the same thing for me, without nearly as much work.

    Thanks of the tip!


    dcr
     
  15. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I'm glad that your mod works for you, but there are a couple of points I'd like to make. First, there's a much easier way to accomplish a 12dB HP on the tweeter, and that's to simply wire a .5mH inductor across the tweeter terminals (Parts Express # 266-816, $ 4.31). This, along with the existing cap, will give a 12 dB rolloff, and give the protection that the tweeter needs but Avatar was too cheap to provide. The crossover frequency will shift a bit, but not enough to be of any real consequence; with the wide overlap of the driver ranges you won't notice it. You may want to switch the polarity, but chances are you won't hear the difference.

    If you really want to improve things go for the Parts Express #290-636 crossover, which has 12dB LP/18dB HP filters, and a tweeter protection circuit.
     
  16. Chaputa

    Chaputa Bass-Not just fo eatin anymore

    I like the looks of the Eminence, but there's no tweeter control on that. Have you used this particular crossover yourself? Just curious given that I'm looking at tweaking the cab a little myself...
     
  17. Chaputa

    Chaputa Bass-Not just fo eatin anymore

    Another quick question, and I apologize if this sounds dumb, but I'm a little concerned on the wattage ratings. The Eminence crossovers are rated at 400 watts. Does this mean that the crossover, on a whole, can only handle that? I know that we rarely would push that much wattage, but I have one of the Kappa's and I am going to be running a minimum of 700 watts RMS through it. Any thoughts or concerns with these crossovers with that mush power or more?
     
  18. The Eminence is an excellent choice. I did not go with it because it is rated @ 8ohms only for the speaker as well as the Tweeter. My cab is 4 ohms
    They have a version that replaces the backplate and has tweeter control as well as speakon connectors. I can order direct from Eminence if you cannot find what you want.
     
  19. Billfitzmaurice,
    Excellent information. It is a shame Avatar could not put this on and simply pass the cost onto the customer at the very least. It would make for a better product with more satisfied customers and less negative reviews on the horn.
     
  20. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The 400 watt rating is enough; the likelyhood that your amp is ever actually putting out full power other than in very brief transients is quite slim. On average you're probably only using 50 to 200 watts, the extra capability is for working headroom.

    I don't use these myself, I build my own crossovers. If you want to 'roll your own' you can get crossover component values for any impedance and crossover frequency at http://www.lalena.com/audio/calculator/xover/

    I never use a tweeter level control, that's best handled by the EQ of the amp. Usually tweeters need padding down because the manufacturer didn't use a decent crossover and you need to pad to limit the levels of out of bandwidth frequencies going to the tweeter. At factory cost that saves them about two bucks per cabinet.